Refrigerator compressor



Oct. 23, 1956 M. Y. WARNER REFRIGERATOR COMPRESSOR Original Filed July16, 1955 5 Sheets-Sheet l fiznfor: flz'lzon K Warner Oct. 23, 1956 M. Y.WARNER 2,767,903

REFRIGERATOR COMPRESSOR Original Filed July 16, 1953 3 Sheets-Sheet 20a. 23, 1956 M. Y. WARNER ,7 7

REFRIGERATOR COMPRESSOR Original Filed July 16, 1953. 3 Sheets-Sheet 5United States Patent REFRIGERATOR COMPRESSOR Original application JulyDivided and this application December 1, 1954, Serial No. 479,802

3 Claims. (Cl. 230-58) This invention relates generally tomotor-compressor units, and more specifically to an improved hermeticmotor-compressor unit for use in a refrigeration system wherein themotor is of the axial air-gap type. This application is a division of anoriginal application by the same inventor, filed July 16, 1953, SerialNo. 368,293, and entitled Refrigerator Compressor.

Hermetic motor-compressor units find important use in the refrigerationart, and it is of further importance in that art that these hermeticmotor-compressor units have as narrow a width as possible to permit thedesign of refrigerator cabinets wherein only a small proportion of theavailable space need be alloted to the motor-compressor unit. One of thechief advantages of an axial air-gap motor is the narrow width of themotor as measured parallel to the axis of rotation. tional motor ofsimilar horsepower this dimension is considerably less. Therefore theobject of this invention is to provide a hermetic motor-compressor unitwherein the motor is of the axial air-gap type and wherein the hermeticunit has a possible width substantially less than is possible with thehermetic motor-compressor units presently known in the art.

It is a feature of this invention that a novel oil pump and thrustbearing are provided which maintains the width of the assembly withinnarrow limits.

It is another feaure of this invention that a novel arrangement isprovided for lubricating the cylinder of the compressor portion of theunit.

-It is a further feature of this invention that a novel counterweight isprovided with novel means for mounting the counterweight to balance thecrankshaft.

It is another feature of this invention that novel structure is providedfor suspending the motor and the compressor within the hermetic casingwith means for adjustment of the suspension.

It is a further feature of this invention that a novel snubber isprovided to prevent unnecessary vibration of the outlet line of thecompressor.

Other objects and features of the present invention will be apparentupon a perusal of the following specification and drawings of which:

Figure l is a top plan view of the unit with the upper part of thecasingremoved;

Figure 2 is a cross sectional view of the assembly shown in Figure 1taken along the line 22; a

Figure 3 is an exploded isometric View of the combination oil pump andthrust bearing;

Figure 4 is a diagrammatic view of the snubber arrangement for reducingunwanted vibrations of the outlet line of the compressor; and I Figure 5is a plan View of the counterweight for balancing the crankshaft.

The present embodiment is the preferred embodiment, but it is to beunderstood that changes can be made in the present embodiment by oneskilled in the art without departing from the spirit and scope of thisinvention.

Generally, the motor and the compressor are mounted 16, 1953, Serial No.368,293.

Compared to a conven 2,767,903 Patented Oct. 23, 1956 within a casingcomprising a lower pan 10 and an upper pan 11. These two pans aresubstantially bowl-shaped and are sealed at the edges thereof to form ahermetic casing. Referring to Figure 2, the axial air-gap motorcomprises substantially the lower half of the structure shown thereinand the compressor comprises substantially the upper half of thestructure shown therein. motor is generally designated with thecharacter 13 and the compressor is generally designated with thecharacter 12. The .motor is generally mounted within and sup ported by asubstantially bowl-shaped stator support frame 14, and the compressor 12is generally mounted within and supported by a substantially bowl-shapedcrankcase 15. The crankcase 15 and the stator support frame 14 arerigidly connected together by three bolts 16, which .project throughthree holes 17 provided in the periphery of the crankcase 15, and whichare threaded into three tapped holes 18 in the periphery of the statorsupport frame 14. The three bolts 16 are triangularly disposed to eachother as can be easily seen in Figure 1. A spring hook 19 is attached tothe top of the crankcase 15 by the bolt 16, as can be seen in Figure 2.Two other spring hooks 19 are provided which are mounted to thecrankcase 15 by the other two bolts 16. It is intended that the unit bemounted longitudinally in a horizontal plane with the compressor portion12 disposed above the motor portion 13. The internal assembly isresiliently suspended by three suspension members 20. Each of thesesuspension members 20 comprises a mounting element 21, a coiled spring22, and a spring hanger 23. The mounting element is connected to theunderside of the upper pan 11. To the mounting element 21, the springhanger 23 is rigidly connected. The spring hanger 23 is generallycone-shaped, and the portion thereof which is adjacent to the mountingelement 21, has a number of threads formed thereon which arecomplementary to the turns of the coiled spring 22. Thus the upper endof the coiled spring 22 is mounted over and threaded onto the springhanger 23. The lower portion of the coiled spring 22 is formed to have ahook thereon. This hook is mounted in cooperation with the spring hook19 to thereby resiliently suspend the motor-compressor unit within thecasing. Since the coiled spring 22 is threaded onto the spring hanger23, it may easily be seen that the effective length of the coiled spring22 may be increased or decreased by threading and unthreading the coiledspring 22 on the spring hanger 23 in increments of For lubrication andcooling of the unit a quantity of lubricating oil is provided. Thelubricating oil 24 is disposed within the lower pan 10 as can be easilyseen in Figure 2, and the amount used is that amount sufi'icient tosubstantially submerge the motor 13.

The motor 13 will be described in detail first. As previously noted, themotor is generally supported and contained within a bowl-shaped statorsupport frame 14.

The stator 25 is rigidly connected to the concave side of the statorsupport frame 14 by means of bolts 26. The stator 25 includes the fieldwindings 9 which are connected to a cable 8. The cable 8 is in turnconnected Without the lower pan 10 by the terminal assembly 17. Abearing 27 is provided through the center of the stator support frame14, and within this bearing 27 the crankshaft 28 is rotatively mounted.The center portion of the convex side of the stator support frame 14 isgenerally formed with a depression therein. The tip of the crankshaft 28projects into this depression and a number of holes 29 are formedthrough the stator support frame 14 from the concave side thereof intothe depression. The depression is enclosed by the oil pump and thrustbearing means which are shown generally with the character 30. Theportion 31 of the depression of the stator support frame 14 is formedwith an involute curve.

The

The rotor for the motor is shown generally with the character 32. Theportion of the crankshaft 28 which cooperates with the rotor 32 isshaped to have a hub 34 and a ring 35. The hub 34 and the ring 35 aretapped for four bolts 36. The rotor 32 is mounted over the hub 34 andagainst the ring 35 with a light press fit. The major proportion of therotor 32 is fabricated as a continuous strip of steel wound in a rolland integrally cast with two rings of aluminum and with aluminum barspassing through the steel. The roll of steel 37 has radial holes aboutits periphery and upon casting the aluminum completely fills these holesto form an integral part with the roll of steel. The inner aluminum ringis tapered as shown at 38. The complete assembly of the rotor alsocomprises a rotor support disk 39 and a spacer ring 40. The rotorsupport disk 39 has four holes therethrough which are aligned forcooperation with the bolts 36. When the rotor 32 is mounted to thecrankshaft 28, the bolts 36 are tightened to cause the rotor supportdisk 39 to be bent against the rotor spacer ring 40 and the bevel 38 ofthe inner aluminum ring of the rotor 32.

For a description of the oil pump and thrust bearing reference is madeto Figures 2 and 3. The oil pump and thrust bearing 30 comprises theimpeller retainer 44, the impeller 45, the thrust plate facing 46, andthe plate 47. The crankshaft 28 is formed with a hole 42 extendingaxially therethrough. The crankshaft 28 is further formed to have twonotches 43 formed at the one end thereof which is disposed within thedepression formed within the convex surface of the stator support frame14. The impeller retainer 44 is formed of a rectangularly shapedmaterial with two prongs extending upward therefrom. The two prongs ofthe impeller retainer 44 are pressed into the two notches 43 on the endof the crankshaft 28 to thereby maintain the impeller retainer 44thereagainst. The impeller retainer 44 also has a hole through thecenter thereof and this hole cooperates with the bore 42 in thecrankshaft 28. The impeller 45 is generally circular in shape, and has aplurality of vanes extending from the circular surface thereof, as caneasily be seen in Figure 3. The impeller 45 is mounted in cooperationwith the impeller retainer 44 so that the edges of the impeller retainer44 are pressed between the vanes of the impeller 45. The impeller 45also has a hole formed through the center thereof which cooperates withthe hole through the center of the impeller retainer 44 and the bore 42of the crankshaft 28. The impeller 45 when so mounted operativelycooperates with the involute curve formed within portion 31 of thedepression on the convex side of the stator support frame 14, so thatany liquid fed centrally of the impeller 45, when the crankshaft 28 isrotating, will be forced outwardly from the vanes of the impeller 45 andin the involute curve. The thrust plate facing 46 which is formed of ahard metal, and the thrust plate 47 are mounted together and rigidlyconnected over the depression in the convex side of the stator supportframe 14. The thrust plate facing 46 is mounted between the thrust plate47 and the stator support frame 14. The thrust plate facing 46 and thethrust plate 47 are rigidly mounted over the depression on the convexside of the stator support frame 14 by four bolts 48 which projectthrough four holes in the thrust plate facing 46 and the thrust plate47, and are threaded into four tapped holes in the stator support frame14. The thrust plate facing 46 is further formed to have four holes 49formed therethrough, and these holes 49 are positioned beneath the vanesof the impeller 45. The thrust plate facing 46 is further formed to havefour slots 50 formed therethrough. The four slots 50 intersect eachother at an opening in the center of the thrust plate facing 46, as caneasily be seen in Figure 3. These slots 50 are positioned beneath thecircular flat portion of the impeller 45. The thrust plate 47 has fourchannels 51 formed therein.

These channels 51, which are substantially wider than the slots 50, andwhich may easily be seen in Figure 3. are so positioned as to intersectat an opening in the center thereof. Each of the slots 51 are formed ofa length equal to the length of each of the slots 50 plus the distancefrom the end of each of the slots 50 to the outermost side of the holes49. The slots 50 of the thrust plate facing 46 are not centered directlyabove the channels 51 in the thrust plate 47, but are positionedoff-center thereof in a direction dependent upon the direction ofrotation of the impeller 45. Assuming for purposes of explanation thatthe impeller 45 is rotating in a counterclockwise direction as viewed inFigure 3, then the side 54 of each of the slots 50 would be the leadingedge of these slots and the side 53 of each of these slots would be thetrailing edge of these slots. The slots 50 are then positioned inrelation to the channels 51 so that the leading edge of each of theslots 50 is positioned upon the center line of each of the channels 51.Thus the leading edges of each of the slots 50 overhang the channels 51a substantially greater amount than do the trailing edges of each of theslots 50. Thus when the motor 13 is operating, the thrust exerted by thecrankshaft 28, due to the magnetic attraction between the rotor 37 andthe stator 25, will be distributed throughout the area between theimpeller 45 and the thrust plate facing 46, and the thrust plate facing46 will act as thrust shoe. Now if oil is supplied to the channels 51, awedge-shaped film of oil will be formed between the trailing and leadingedges of the slots 50 as the crankshaft 28 is rotating. This will resultin a lubrication of the thrust bearing similar to that supplied by thewell known Kingsbury thrust bearing. To discuss the operation of the oilpump, when the crankshaft 28 is rotating, the oil 24 disposed within thelower pan 10 will flow into and through the holes 29 in the statorsupport frame 14. This oil will flow into the space centrally of theimpeller 45. The rotating impeller 45 will move the oil radially thereofinto the vanes thereof. From the vanes of the impeller 45, the oil willflow downward through each of the openings 49 in the thrust plate facing46. From the openings 49, the oil will flow into and through thechannels 51 of the thrust plate 47. From the channels 51 of the thrustplate 47, a portion of the oil will flow upward through the centerthereof, through the center of the thrust plate facing 46, through thehole in the center of the impeller 45, through the hole in the center ofthe impeller retainer 44 and into and through the bore 42 of thecrankshaft 28. Another portion of the oil flowing through the channels51 will flow upward through the slots 50 to lubricate the thrust bearingpreviously described.

To discuss the detailed structure of the compressor 12 reference is madeto Figures 1 and 2. The crankcase 15 comprises a substantiallybowl-shaped casting, which as previously described is mounted to theperipheral edge of the stator support frame 14 by the bolts 16. Tofurther aid in the alignment of the crankcase 15 with the stator supportframe 14 three dowels 55 are provided. A bearing 56 is formed throughthe center of the crankcase 15 as can easily be seen in Figures 1 and 2.The bearing 56 supports the upper end of the crankshaft 28. The bore 42extends upwardly through the crankshaft 28 and near the upper endthereof is formed to slant away from the axis of rotation of thecrankshaft 28 as can be seen in Figure 1. Thus when the crankshaft 28 isrotated by the motor 13, the oil which flows from the oil pump 30 upwardthrough the crankshaft 28 and out of the top thereof is given a lateralcomponent of motion. Thus as the crankshaft 28 rotates, the oil issprayed about the inner surface of the upper pan 11 and will then fiowdownward along the inner walls of the casing to the lower pan 10. As theoil flows along the inner surfaces of the casing, heat from the oil willbe conducted to the casing thereby cooling the oil. The

meteor:

crankshaft 28 is further provided with an eccentric 57 formed as a partthereof. A channel 58 is formed through the eccentric 57 to the bore 42of the crankshaft 28 to provide lubrication for the eccentric 57. Afurther channel 59 is formed radially from the bore 42 to the outersurface of the crankshaft 28 which is disposed within the bearing 56.The oil flowing through the channel 59 serves to lubricate the bearing56 and the cylinder 60. The specific structure cooperating with thechannel 59 to provide lubrication for the cylinder 60 includes adepression 61 formed in the upper surface of the crankcase 15, and twoholes 62 and 63. The hole 62 is formed in the crankcase 15 from an upperportion'of the depressionp61 into the bearing 56 and in verticalalignment with the channel 59. The hole 63 is formed through thecrankcase 15 from the lowest portion of the depression 61 downward intothe cylinder 60. Whenever the crankshaft 28 is rotated to the positionwherein the channel 59 is in horizontal alignment with the hole 62, oilflowing upward through the bore 42 will flow through the channel 59,through the hole 62 into and filling the depression 61. From thedepression 61 the oil will flow downward through the hole 63 into thecylinder 60. The cylinder 60 is cast as an integral portion of thecrankcase 15 on the concave side thereof as can be easily seen in Figure2. The cylinder 60 is further formed so that the longitudinal axisthereof is at a right angle to the axis of rotation of the crankshaft28. A piston 64 is slidably mounted within the cylinder 60. A connectingrod 65 is rotatively mounted about the eccentric 57 and is pivotallyconnected to the piston 64 by a wrist-pin 66, as can be easily seen inFigure 2. It can thus be seen that as the motor 13 is operated to rotatethe shaft 28, the piston 64 will operate within the cylinder 60, and oilwill flow from the hole 63 to lubricate the piston 64 and the cylinder60. A cylinder head 67 is mounted over the cylinder 60 in cooperationwith the piston 64. The cylinder head 67 is mounted to the crankcase 15by means of the bolts 68. Within the cylinder head 67 intake and exhaustvalves 69 are mounted. These valves may be of any type well known in theart, and therefore the construction thereof will not be described indetail. The crankcase 15 is further provided with two mufller chambers70 and 71. These muflier chambers 70 and 71 are cast as integral partsof the crankcase 15, the muffler chamber 70 serving as an intake mufflerand the muflier chamber 71 serving as an exhaust muffler. A hole 72 inthe top of the Inufiler chamber 70 is provided when the crankcase 15 iscast to aid in the casting thereof. This hole 72 is sealed by a plug 73.A hole 74 is formed through an end wall of the mufller chambers 71 toaid in the casting thereof and to serve as an outlet from the mufllerchamber 71. An opening 75 is formed through one wall of the mufilerchamber 70. This hole 75 is formed on the concave side of the crankcase15, so that refrigerant gases are drawn into the muffler chamber 70through the hole 75, from the concave side of the crankcase 15, from theopen spaces about the periphery of and between the crankcase 15 and thestator support frame 14, and from a tube 76 connected through the upperpan 11 of the casing. Any refrigerant gases which enter the muffierchamber 70 are delivered to the cylinder head 67 and the cylinder 60through a channel 77 formed through the crankcase 15 from the mufflerchamber 70 to the cylinder head 67. The exhaust mufiler chamber 71 isconnected to the cylinder head 67 and the cylinder 60 by means of achannel 78 extending from the exhaust mufiier chamber 71 to the cylinderhead 67. An exhaust mufiier chamber cover 79 is provided over theopening 74 of the exhaust muffler chamber 71. To the exhaust mufllerchamber cover 79, a length of tubing 80 is connected. This length oftubing 80 extends from the exhaust muffier chamber cover 79 about theinside of the upper pan 11 in one complete turn, and is then connectedwithout the upper pan 11 by means of the tube 82. A bolt 83 extendsthrough the exhaust muffler chamber cover 79 to maintain the exhaustmufller chamber cover 79 against the opening 74. This bolt 83 isthreaded into a tapped hole in the crankcase 15.

To next describe the operation of the compressor 12, when connected in arefrigeration system (not shown), refrigerant gases are drawn into thetube 76 between the peripheral edges of the crankcase 15 and the statorsupport frame 14, within the concave side of the crankcase 15, into andthrough the hole 75, into the intake mufiler chamber 70, through thetube 77, into the cylinder head 67 and the cylinder 60, through thecylinder head 67 into and through the tube 78, into the muffler chamber71, through the hole 74 into the exhaust muffier chamber cover 79,through the tubing and out of the unit through the length of tubing 82.

To balance the crankshaft 28, a specific counterweight 84 is provided. Aplan view of the counterweight 84 can be seen in Figure 5, and across-sectional view thereof, taken along the line 2-2 of Figure 1, canbe seen in Figure 2. The counterweight 84 is formed in the general shapeof a semi-circular ring. The lower portion of the inner periphery of thecounterweight 84 is formed with a bevel 85 as can be seen in Figure 2.The crankshaft 28 is further shaped to have a circular beveled portion33. The bevel 85 of the counterweight 84 matches the beveled portion 33of the crankshaft 28. The outer periphery of the counterweight 84 isformed with two slots 86 therein. These slots 86 are spaced apart adistance equal to the spacing between two of the bolts 36 which maintainthe rotor 32 mounted to the crankshaft 28. The counterweight 84 isfurther provided with a counterbored hole 87. Further, a portion of thehub 34, between the aforementioned two bolts 36, is tapped so that abolt 88 may be projected through the hole 87 and threaded thereinto.When the counterweight 84 is mounted to the crankshaft 28, the two bolts36 are positioned within the two slots 86 and the bevel 85 cooperateswith the beveled portion 33, and as the bolt 88 is tightened, thecounterweight 84 is forced downward and outward until the two bolts 36are tightly wedged against the two slots 86.

As previouslydescribed, the discharge line or length of tubing 80 isconnected to the exhaust mufiler cover 79, and is further brazed to thelength of tubing 82, and is positioned to make a complete loop about theinside of the upper pan 11. The purpose of this loop is to providesuflicient flexibility in the discharge line connection between thecompressor 12 and the upper pan 11 so as to allow freedom of movement ofthe motor-compressor unit with respect to the casing. To dampen anyresonant vibrations that may occur in the discharge line 80, a snubberspring 96) is provided. The snubber spring 90 is held by spring actionbetween the discharge line 80 and one of the springs 22 of one of thehanger assemblies 20. As shown, the snubber spring 90 is positionedapproximately midway of the discharge line 80 and midway of the coiledspring 22. Thus a point located midway on the coiled spring 22 moves,with respect to the casing, approximately one-half the distance that themotor compressor assembly moves. The midpoint on the discharge line 80will likewise move about one-half the distance that the motor-compressorassembly will move. Thus movement of the motor-compressor assembly withrespect to the casing is not restrained by the snubber spring 90, butany vibration that occurs in the discharge line 80, other than theforced vibration at the frequency at which the motor-compressor assemblyis vibrating will be opposed by the restraining action of the snubber.For a detailed description of the operation of the snubber spring 90reference is made to Figure 4 wherein the structure is showndiagrammatically. As shown the motorcompressor unit 12 and 13 is free tovibrate in any direction. It can be seen that the use of the snubberspring 90 upon the discharge line 80 does not interfere with the normalmovements of the motor-compressor unit 12 and 13 induced by unbalance ofmoving parts and by variationsin torque load. In relation to thevibrations of the motor-compressor unit 12 and 13, it may be seen thatif the flexible discharge line 80 should happen to be resonant or nearresonance to some disturbing frequency, at some load condition, thedischarge line 80, between the ends thereof, might vibrate at a greateramplitude or at a ditferent phase than the end of the loop fastened tothe compressor. This condition would produce relative motion between thetube loop and the coiled spring 22. The snubber spring 99 connectedbetween the discharge line 80 and the coiled spring 22, between the endsof the discharge line 80, would exert frictional restraining forces uponsuch relative motion.

Having described the invention What is considered new and desired to beprotected by Letters Patent is:

1. In a device of the class described, a casing fashioned with anopening therethrough, a motor-compressor unit having an outletthereinto, means including at least one coiled spring resilientlysuspending said motor-compressor unit within said casing, a length oftubing, one end of said length of tubing connected to the outlet of saidmotor-compressor unit, the other end of said length of tubing connectedwithout said casing through the opening in said casing, said length oftubing being formed to have at least one complete loop within saidcasing, whereby said length of tubing does not substantially interferewith the resilient suspension of said motor-compressor unit, a snubberspring attached to said length of tubing between the ends thereof, saidsnubber spring further positioned to contact said coiled spring betweenthe ends thereof, so that said length of tubing will not vibrate at aresonant frequency thereof other than the frequency of vibration of saidmotor-compressor unit when said motor-compressor unit vibrates relativeto said casing.

2. In a. device of the class described, a casing fashioned with anopening therethrough, a motor-compressor unit having an outletthereinto, means including a plurality of coiled springs resilientlysuspending said motor-compressor unit within said casing, a length oftubing, one end of said length of tubing connected to the outlet of saidmotor-compressor unit, the other end of said tubing connected withoutsaid casing through the opening in said casing, said length of tubingbeing formed to have one complete loop within said casing, whereby saidlength of tubing does not substantially interfere with the resilientsuspension of said motor-compressor unit relative to said casing, asnubber spring positioned within said casing and disposed so as toresiliently engage simultaneously a portion of said length of tubing andone of said coiled springs, whereby said length of tubing will beprevented from vibrating at any resonant frequency other than thefrequency of vibration of said motor-compressor unit when saidmotor-compressor unit is vibrated by the operation thereof, and wherebya minimum of the vibrations of said motor-compressor unit will betransferred to said casing through said length of tubing.

3. in a device of the class described, a casing fashioned with anopening therethrough, a motor-compressor unit having an outletthereinto, means including a plurality of coiled springs resilientlysuspending said motorcornpressor unit within said casing, a length oftubing, one end of said length of tubing connected to the outlet of saidmotor-compressor unit, the other end of said tubing connected withoutsaid casing through the opening in said casing, said length of tubingbeing formed to have one complete loop within said casing, whereby saidlength of tubing does not substantially interfere with the resilientsuspension of said motor-compressor unit, a snubber spring attached tosaid length of tubing substantially at the center of said loop, saidsnubber spring further positioned to contact one of said coiled springssubstantially at the center thereof, so that when said motor compressorunit moves a certain amount in any given direction said center of saidloop will only move substantially one-half of that amount in cooperationwith the movement of the contacted spring to thereby allow free movementof the motor-compressor and to dampen any vibration of said length oftubing relative to said contacted coiled spring.

References Cited in the file of this patent UNITED STATES PATENTS

